Acute kidney injury (AKI) and septic shock associated AKI (SSAKI) requiring renal replacement therapy (RRT) are significant complications in intensive care unit (ICU) patients with an associated mortality rate exceeding 50%. The need for novel therapeutics that are specifically approved for pediatric AKI/RRT use is driven by the nearly 50% mortality rates of pediatric patients with this disorder. The SCD is a novel device containing bundled biomimetic polysulfone fibers which selectively bind/sequester and deactivate leukocytes (LE) in a dialysis extracorporeal blood circuit, resulting in an immunomodulatory effect in the systemic inflammatory response associated with AKI and SSAKI. The SCD, combined with regional citrate anticoagulation, is a novel therapeutic application utilizing biocompatible membranes that allow LE attachment in a calcium low environment during regional citrate anticoagulation resulting in a diminution in the LE activated state. The SCD has been studied in prior clinical trials of AKI. This proposal will study the safety and efficacy of SCD therapy in pediatric patients with AKI requiring CRRT therapy. Specific Aim 1 will evaluate this innovative approach in pediatric ICU patients of greater than 20 kilograms (kg) in body weight. Specific Aim 2 will assess this approach in pediatric patients with body weights between 8 and 20 kg utilizing a SCD one-fifth the size of the current SCD.